Wash the fish, dab dry, season with salt and lemon juice. Clean, wash and cut the peppers into strips. Clean and wash spring onions. Brush aluminium foil with oil and spread the strips of bell peppers on top.
Place fish on top of the vegetables and sprinkle with chilli. Place a spring onion on each of them. Pluck the thyme leaves from the stalks and sprinkle over them. Seal the foil and cook in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 15 minutes.
Put fish and vegetables on plates and garnish with thyme and lemon slices. Ciabatta tastes good with it.